Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
In September, the meteorological conditions change slightly, with the average high-temperature moving from a warm 78.8°F (26°C) in August to an agreeable 73.2°F (22.9°C). Mount Vernon in September anticipates an average nighttime temperature of 54.5°F (12.5°C).Humidity
In Mount Vernon, the average relative humidity in September is 80%.Rainfall
In Mount Vernon, in September, during 12.1 rainfall days, 1.3" (33mm) of precipitation is typically accumulated. Throughout the year, there are 148.8 rainfall days, and 18.9" (480mm) of precipitation is accumulated.Snowfall
May through October are months without snowfall.Daylight
In Mount Vernon, the average length of the day in September is 12h and 27min.On the first day of September, sunrise is at 6:58 am and sunset at 8:01 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 7:13 pm EDT.
Sunshine
In September, the average sunshine is 8h.UV index
In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for average individuals.Note: An average UV index of 4 in September transforms into this advice:
Undertake precautions - Guarding against sun damage is counselled. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September in Mount Vernon?
How many days does it rain in September?
When it does not snow?
What is the average length of the day in September?
What time are sunrise and sunset in September in Mount Vernon?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Mount Vernon, OH
- Average high temperature in September: 73.2°F
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (31.5°F).
- Average low temperature in September: 54.5°F
The month with the highest average low temperature is July (62.1°F).
The coldest month (with the lowest average low temperature) is January (19.2°F).
Average pressure in September
Mount Vernon, OH
- Average pressure in September: 30.04"Hg
The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
Mount Vernon, OH
- Average wind speed in September: 6.3mph
The windiest month (with the highest average wind speed) is January (10.1mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).
Average humidity in September
Mount Vernon, OH
- Average humidity in September: 80%
The month with the highest relative humidity is January (86%).
The months with the lowest relative humidity are March, April and November (78%).
Average rainfall in September
Mount Vernon, OH
- Average rainfall in September: 1.3"
The wettest month (with the highest rainfall) is May (2.36").
The driest month (with the least rainfall) is February (1.18").
Average rainfall days in September
Mount Vernon, OH
- Average rainfall days in September: 12.1 days
The month with the highest number of rainy days is May (18.6 days).
The month with the least rainy days is February (6.9 days).
Average snowfall in September
Mount Vernon, OH
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.65").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Mount Vernon, OH
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Mount Vernon, OH
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 8h and 0min
The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 12min).
Average sunshine days in September
Mount Vernon, OH
- Average sunshine days in September: 16.2 days
The month with the most sunshine days is November (19 days).
The month with the least sunshine days is May (10.5 days).
Average UV index in September
Mount Vernon, OH
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in September
Mount Vernon, OH
- Average cloud cover in September: 38
The month with the most cloud cover is January (Cloud cover 67).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Mount Vernon, OH
- Average visibility in September: 5mi
The months with the highest visibility are February, March, April, May, June, October, November and December (6mi).
The months with the lowest visibility are January, July, August and September (5mi).
Mount Vernon, Ohio, USA
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